Question Regarding Mobility Between FI and CO Classifications

Hello!

I am currently in an FI-02 position and have applied for a CO-02 position. If I wanted to return to the FI classification afterward, would I be able to apply to FI-03 processes as an at-level candidate, given that the salary difference between the top steps of the two classifications is less than 6%?

The position I applied for interests me a great deal. The only thing giving me pause is that it is in a different classification, and I am a CPA. My current position is an acting assignment, and the CO-02 position would be a promotion.

Thank you for your time and guidance.